Application effect of high-density electrical method on detecting artificial filling layer: A case study of Chengjiangshan area of Huaibei City

High-density electrical method has been proved to be an effective method for probing shallow sedimentary layers.It is principally used to identify the boundary between the Quaternary soil layer and bedrock according to the vertical change of apparent resistivity.However,the artificial filling layer has the characteristics of heterogeneity and high porosity,which makes it challenging to detect the artificial filling layer by high-density electrical method.The key to solve this problem is to detect the difference of conductivity between the filling layer and the underlying bedrock.This paper takes the land in Chengjiangshan area of Huaibei City,Anhui Province as the detection target.On the basis of fully analyzing the physical properties of the artificial filling layer,two-dimensional high-density electrical survey and inversion are used to define the thickness of the artificial filling layer.The research shows that the highdensity resistivity method has obvious advantages in delineating the distribution of bedrock and the thickness of the filling layer,and the reliability of the high-density electrical method in the detection of the artificial filling layer,and delineates the scope of the filling layer is verified by the borehole data.

Contrast between 2D inversion and 3D inversion based on 2D high-density resistivity data

The 2D data processing adopted by the high-density resistivity method regards the geological structures as two degrees, which makes the results of the 2D data inversion only an approximate interpretation;the accuracy and effect can not meet the precise requirement of the inversion. Two typical models of the geological bodies were designed, and forward calculation was carried out using finite element method. The forward-modeled profiles were obtained. 1% Gaussian random error was added in the forward models and then 2D and 3D inversions using a high-density resistivity method were undertaken to realistically simulate field data and analyze the sensitivity of the 2D and 3D inversion algorithms to noise. Contrast between the 2D and 3D inversion results of least squares inversion shows that two inversion results of high-density resistivity method all can basically reflect the spatial position of an anomalous body. However, the 3D inversion can more effectively eliminate the influence of interference from Gaussian random error and better reflect the distribution of resistivity in the anomalous bodies. Overall, the 3D inversion was better than 2D inversion in terms of embodying anomalous body positions, morphology and resistivity properties.

Effects of indium doping concentration on the morphology and electrical properties of one-dimensional SnO_2 nanostructures prepared by a molten salt method

In this paper,indium doped SnO2 nanorods and nanowires have been prepared by the molten salt method,and the effects of indium doping concentration on the morphology and electrical properties of one-dimensional(1D) SnO2 nanostructures have been studied.It is found that indium doping concentration can affect the epitaxial growth,morphology and the electrical conductance of 1D SnO2 nanostructures.It is also found that the element made by using 6 mol% indium doped SnO2 nanorods responds to nitrogen gas.

稳定电流场有限元法模拟研究

以直流电场有限元方法为基础，从二维电性介质线源有限元模拟出发，深入探讨了改进复杂电性结构理论模型有限元正演资料仿真性、有效性的方法．首先，用加里津（Garlerkin）方法推导了稳定电流场的有限元方程，得到了人为截断的边界条件；研究了快速形成系数矩阵的模块化方法以及自动识别地电参数和电性分界面的网格自动剖分软件燃后讨论了不同边界情况下的数值模拟情形，指出了各自的物理含义及吸收效果，最后由模型计算对本文方法进行了检验．

高压输电线塔基煤矿采空区的高密度电阻率法探查研究

煤矿采空区的塌陷与变形对高压供电线塔基的稳定构成了极大的威胁.使用高密度电法对塔基附近的地质结构进行了探测,应用二维和准三维反演方法确定了地下电阻率分布形态,以此为基础推断解释了塔基附近煤矿采空区的位置和形态,并对塔基的加固处理提出了建议.

MATLAB在有限差分法中的应用

将MATLAB应用于有限差分法的正演计算中 ,充分发挥了其强大而方便的功能。通过对二维稳定电流场模型的试算表明 ,MATLAB在解决实际的工程和数学问题中 ,与其它计算机程序设计语言C、FORTRAN相比 ,具有使用更为简便、语句功能更强 ,用户界面良好的特点 ,适合于在工程计算 ,尤其是物探数据处理领域推广应用。

电测深曲线二维反演技术及应用

本文对应用有限元及阻尼最小二乘法进行电测深二维反演解释技术做了进一步的研究。在区域网格剖分方法、有限元系数矩阵的合成、雅可比矩阵的计算及法方程的解法等方面进行了改进。由此在微机和工作站上设计了程序软件，经过对理论电测深曲线及实测电测深曲线进行的二维反演解释，结果表明，在微机和工作站上实现的二维反演解释软件可以用于实际测深资料的解释。

大型电机二维温度场的网络拓扑法计算

从传热学的基本理论出发,通过离散积分形式的热传导方程,构造出了网络拓扑法的通用计算格式。采用网络拓扑法对具有强迫通风系统的电机温度场进行了分析和计算,得出的计算结果说明网络拓扑法是一种简单易行、具有较高精确度的计算方法。

二维孔隙介质中重非水相液体饱和度测定与分析

在二维均质饱和孔隙介质中利用光透法与高密度电阻率法定量监测重非水相液体(DNAPL)的运移过程与饱和度。将光透法与高密度电阻率法相结合,进行高密度电阻率法对DNAPL在饱和多孔介质中渗流过程的定量监测。在二维砂箱中进行DNAPL的入渗试验,应用光透法与高密度电阻率法进行动态监测,分别利用CCD相机、LCR数字电桥采集数据。光透法的数据处理采用"水-DNAPL"两相中DNAPL饱和度的计算公式。而高密度电阻率法的数据处理是将获得的电阻值数据转化为电阻率值,然后利用Archie公式获得重非水相液体的饱和度空间分布。Archie公式中参数β值本文采用与光透法相结合的新方法来获取,克服了传统方法获取β值时存在的困难。根据不同时刻的饱和度空间分布可以估算注入砂箱内的DNAPL总量,并将其与实测的入渗量进行对比。结果表明,与光透法结合后的高密度电阻率成像法能定量监测饱和孔隙介质中DNAPL的入渗过程,且估算的DNAPL入渗量与实测值比较吻合,提出的基于光透法计算β值的新方法是有效且可行的。

雷电水平电场时域近似算法研究及精度验证

雷电水平电场是计算雷电感应过电压的关键参数。为了准确高效的求解出雷电水平电场,利用Barbosa和Paulino所提出的雷电水平电场时域近似算法（B-P方程）对距离闪电通道100~1 000 m范围内雷电水平电场进行模拟,分析了不同雷电参数及大地电参数对水平电场特性所产生的影响,并应用2-D FDTD方法对B-P方程的精度进行检验。结果表明：若模拟中地面电导率σ设置越低、观测点距地面高度h设置越低、观测点到闪击点距离r0设置越远、回击速度v设置越大时,电磁场所包含的高频分量比重越大,模拟出水平电场波形的双极性特征越明显;相比于首次回击电流,当模拟中采用继后回击电流时,模拟出水平电场波形的双极性特征更明显;除了电导率σ较低时（σ≤0.001 S/m）B-P方程的计算精度会受传播效应的影响外,其模拟出的水平电场波形与2-D FDTD的模拟结果基本一致,且B-P方程的峰值计算误差均在±5%之内。综上,由于B-P方程的计算时间仅为0.01 s左右,因此在提高计算效率的同时能保证较好的计算精度。

不同手术及缝合方式治疗中重度宫颈上皮内瘤变的临床观察

目的:探讨中重度宫颈上皮内瘤变(CINⅡ-Ⅲ)行宫颈锥切治疗的不同止血方式。方法分析75例在阴道镜下活检,病理诊断 CINⅡ-Ⅲ患者,其中行宫颈环形电切(LEEP)术治疗的40例,行宫颈冷刀锥切采用二、二、二式(甲、乙、丙、丁)缝合的35例,对比两组手术后的出血、宫颈残端感染、残端愈合、及病理诊断切缘情况。结果 LEEP术中出血超过20 mL者15例,占37.5%;术后宫颈残端感染者10例,占25%;病理诊断切缘阳性者5例,占12.5%;术后2个月残端愈合10例,占25%。宫颈冷刀锥切采用二、二、二式(甲、乙、丙、丁)缝合术后出血超过20 mL者0例,占0%,术后宫颈残端感染者2例,占5.7%;病理诊断切缘阳性者0例,占0%,均明显低于LEEP术组。术后2个月残端愈合35例,占100%,均明显高于LEEP术组。结论宫颈残面采用二、二、二式(甲、乙、丙、丁)缝合应用于宫颈冷刀锥切术,较LEEP术止血效果好,感染机会小,疤痕少,对标本切缘的病理诊断无影响,残端愈合快。